The Turkish government has pledged to re-focus on EU accession talks
Turkish Prime Minister Recep Tayyip Erdogan is in Brussels for talks on his country's flagging bid to join the EU.
Mr Erdogan said accession remained a "top priority" for Turkey, before holding talks with European Commission President Jose Manuel Barroso.
It is his first visit since 2004, when the EU agreed to open accession talks.
Correspondents say a flurry of democratic reforms to reach that goal has since foundered, and many see 2009 as decisive for Turkey's EU ambitions.
Last week, Mr Erdogan asked a close aide, Egemen Bagis, to be the country's first full-time negotiator for the accession talks.
At the start of his three-day visit to Brussels, Mr Erdogan insisted that EU accession remained a "top priority" for his country.
"I hope there will be a leap in 2009," he told a news conference.
Mr Erdogan said Turkey was working on many of the reforms demanded by the EU, which include changes to its constitution, safeguarding free speech, granting more rights to minorities, and curbing the power of the armed forces.
"We don't ask for privileges, what we ask for is equal and fair treatment," he said.
But he also warned that Turkey might reconsider its support for the Nabucco pipeline - which is intended to bring gas from the Caucasus to Europe, bypassing both Russia and Ukraine - if the so-called energy chapter of the negotiating framework remained blocked.
"If we are faced with a situation where the energy chapter is blocked, we would of course review our position," he said.
The BBC's Oana Lungescu in Brussels says Turkey's opposition could deal a serious blow to the $12bn (9bn euro; £8.1bn) pipeline project, which the EU wants to speed up in the wake of the current gas-price dispute between Russia and Ukraine.
Mr Barroso said pipelines and EU accession talks should not be linked
Later, after talks with European Commission President Jose Manuel Barroso, Mr Erdogan appeared to contradict his earlier warning by saying that Turkey gave its "full support all the time" to the Nabucco pipeline and would never use energy as a weapon.
Mr Barroso meanwhile insisted that the pipeline and accession talks should not be linked.
But he suggested that if Turkey helped Europe diversify its energy supplies, that could help overcome public concerns about such a big Muslim country joining the EU.
The BBC's Sarah Rainsford in Istanbul says Mr Erdogan's trip to Brussels is a chance for Turkey and Europe to breathe new life into their relationship.
After a galloping start, Turkey has made almost no progress passing democratic reforms in the past four years, and patience in Brussels is wearing thin, our correspondent says.
Mr Erdogan's AK Party has been distracted from the reform agenda of late - fighting domestic crises including a court case meant to close it down - and it is unlikely much will change before March, when local elections are scheduled, she adds.
So far, Turkey has opened talks on 10 out of the 35 "negotiation chapters", of which it has provisionally completed just one.
Eight chapters have been frozen because of Ankara's refusal to open up its ports and airports to traffic from Cyprus, an EU member.
Turkey has said it will not do this until the EU takes steps to end the Turkish Cypriot community's economic isolation.
But the EU has said lifting the ban is now "urgent" and threatened to suspend accession talks if it is not done by mid-December.